Air-fuel ratio control device

Abstract

Abstract PURPOSE:To uniformly maintain the air-fuel ratio of an engine irrespective of a lowland or highland position, by providing a plurality of two dimensional maps of rotational speeds v.s. intake-air pipe pressure for giving a compensation value for an optimum basic fuel injection amount during control of exhaust gas recirculation, for each of plural kinds of atmospheric pressures in order to compensate the basic air fuel injection amount. CONSTITUTION:In such an arrangement that an exhaust gas recirculation passage opening and closing means III is controlled by a gap recirculation control means IV in accordance with the result of detection by an operating condition detecting means II including an engine rotational speed detecting section IIA, an intake-air pipe pressure detecting part IIB and an atmospheric pressure detecting means IIC, a plurality of two dimensional maps VI which are set respectively for atmospheric pressures, of rotational speeds v.s. intake-air pipe pressures for giving a compensation values for optimum basic fuel injection amounts when the above-mentioned opening and closing means III is opened. Further, arrangement is such that a basic fuel injection amount which is calculated by a basic fuel injection amount calculating means V in accordance with the result of detection of an engine rotational speed and an intake-air pipe pressure is compensated with an optimum compensating value under the atmospheric pressure upon operation of the engine, which is calculated with the use of the above-mentioned two dimensional maps VI.

Inventors

• 👤 Katsushi Kato
• 👤 克司 加藤
• 👤 Toshiaki Mizuno
• 👤 利昭 水野

Bibliographic Details